Decompression sickness (DCS) is recognized as a multifactorial phenomenon depending
on several individual factors, such as age, adiposity, and level of fitness. The detection
of circulating venous bubbles is considered as a useful index for the safety of a
decompression, because of the relationship between bubbles and DCS probability. The
aim of this work was to study the effects of individual variables which can be assessed
non invasively, on the grades of bubbles detected 60 min, after diving by means of
Doppler monitoring, in a sample of 40 male recreational scuba divers. The variables
investigated were: age, weight, maximal oxygen uptake (VO2max) and percentage of body fat ( % BF). Bubble signals were graded according to the
code of Spencer. The relationships between the bubble grades (BG) and the variables
investigated were studied using two methods: the differences between the average values
of each variable at each BG were analyzed by the Scheffe test. Then we performed the
non-parametric Spearman correlation analysis. Significant differences (P < 0.05) were
found (Scheffe test) between average values of the variables at grade 0 and 3 (age:
P = 0.0323; weight: P = 0.0420; VO2max: P = 0.0484), except for % BF (P = 0.1697). Relationships with P < 0.01 were found
(Spearman correlation) between BG and the variables: age: p = 0.486, P = 0.0024; weight:
p = 0.463, P = 0.0039; VO2max: p = -0.481, P = 0.0027; except for % BF: p = 0.362, P = 0.0237. This work showed
that bubble production after hyperbaric exposures depends on several individual factors.
The effects off age, weight and VO2max are more significant than the effect of % BF. We concluded that to take into account
such variables in decompression tables and diving computer programs should allow to
adapt the decompression procedures to individual risk factors and reduce the DCS probability.
Key words
Recreational diving - bubbles - Doppler monitoring - age - weight - body fat percentage
- maximal oxygen uptake